Concrete paving machine



Nov. 4, 1941. c. w. PIERCE CONCRETE PAVING MACHINE 4 Sheets-Sheet 1 Filed Sept. 5, 1940 i CHHELEJ W P/zecc, INVENTOR.

1941- c. w. PIERCE CONCRETE PAVING MACHINE Filed Sept. 5, 1940 4 Sheets-Sheet 2 0/4/2155 WP/f/ECE, INVENTOR.

Nov. 4, 1941. c. w. PIERCE CONCRETE PAVING MACHINE Filed Sept. 3. 1940 4 Sheets-Sheet 3 01424:: W Pure c5,

INVENTOR. BYWM/W Nov. 4, 1941. c. w. PIERCE CONCRETE PAVING MACHINE Filed Sept. 3, 1940 4 Sheets-Sheet 4 C/fflELEJ W Pxtxac:

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arm/wir- I J H w W \i Patented Nov. 4, 1941 CONCRETE PAVING Charles W. Pierce, La Crescenta, Califl, assignor to ViberGompany, a corporation of California Application September 3, 1940, Serial No. 355,150

Claims.

This invention relates to paving machines, and in particular to a machine for compacting concrete by internal vibration.

One object of my invention is to provide a machine for the placement of concrete in pavements, slabs, and the like, which is of very large capacity and highly efficient in compacting congrete of large aggregates and of low water conent.

Another object is to provide a machine for leveling, compacting and finishing a concrete slab from a mass of concrete upon a roadway.

Another object is to provide a machine which vibrates the concrete in place on a roadbed.

Another object is to provide a machine which vibrates a plastic material such as concrete on a roadbed between crosswise expansion joints, with means for raising and lowering the vibrating mechanism over the crosswise joint members.

Still another object is to provide a mechanism for raising and lowering a gang of vibratory units to avoid crosswise members in the roadway.

A further object is to provide means for holding a gang of tubular vibrators in inclined partly submerged operative position while moving the vibrators through the concrete to compact it.

These and other objects will be apparent from the following description and the drawings in which: Fig. 1 is a side elevation of one form of my paving machine. Fig. 2 is a plan view of the same. Fig. 3 is an enlarged side elevation of the elevating mechanism for the vibrators of my machine. Fig. 4 is a section taken on the line 4-4 of Fig. 3. Fig. 5 is a more detailed elevation, partly in section, of a vibrator unit. Fig. 6 is a front elevation of my machine. Fig. 7 is a cross-sectional view taken on the line 1-1 of Fig. 2; Fig. 8 is a perspective view showing the supporting means for the vibrators.

My paving or concrete placing machine in one form consists of a carriage having side members H and I2 and frame cross members I3, Ii, l5 and It, with rear wheels l8 and I9 mounted on a drive shaft 22 in bearings 28 and 2| attached to the side frame members II and I2, and front wheels 26 and 27 mounted on a drive shaft in 30 in bearings 28 and 29 attached to the main frame. The wheels are preferably flanged and adapted to travel on headers or side boards 32 which form the margins for the pavement. Upon the main frame is mounted a gasoline motor 4| whose main shaft is operatively connected to a generator l2 through the coupling 43. The generator supplies electrical energy for the carriage 45. Suitable speed-reducing mechanism is incorporated with the motor as a unit. The carriage motor 44 drives a countershaft 46 by means of the chain drive 47 and the chain sprockets 48 and 49. The rear wheel drive shaft 22 is actuated through its chain sprocket 23 from the sprocket 59 on the countershaft and the chain 5|. The front wheel drive shaft 30 is actuated through its chain sprocket 3| driven by sprocket 52 on the countershaft and chain 53.-

My machine is provided with a plurality of separate vibratory units of the general type consisting of an elongated tubular housing enclosing a rotary vibratory mechanism and attached to a high-speed motor, the tubular housing being at least partly insertible in the concrete. Each of these vibrator units is supported on movable cross member 60 by means of a yoke 6| at the end of a leaf spring member 82 which is rigidly attached to the movable cross member 60. V

The motor 63 of the vibrator unit is attached to the yoke 6| by bolts 64 and the yoke is attached to the end of the leaf spring by the bolt 65. Upon the movable cross member 60 and intermediate its ends is mounted an elevator motor Behaving a speed reducer 6'! whose shaft 68 is provided with a chain sprocket 69 which drives a sprocket E0 on an elevator shaft ll extending the full width of the machine. Sprocket wheels 12 on the shaft 'H are adapted to ride upon a chain track on racks 73 at either end of the shaft and upon a central rack M intermediate thereof. The elevator shaft H is supported in bearings in vertical plates 15 attached at right angles near the ends of the member 60 and also in a similar vertical plate 16 intermediate the ends and adjacent the elevator motor 66.

Attached to the main frame side members II and I2 and also to a centrally placed parallel brace member 11 between cross members l5 and [6 are attached vertical plates on the top edges of which are geared tracks or racks 13 upon which the sprocket wheels 12 are supported and over which they may travel. In elevation this rack slopes first downwardly and forwardly and then curves downwardly and forwardly, and upon this travels the entire vibrator mechanism including the cross support member 60, the elevator motor 66 and the vibrator units 56. In the center plate 80 below the rack is cut a cam slot 18 of shorter length than the rack, in which the motor 44 which is controlled through the switch 55 cam roller 19 attached to the plates 16 operates and determines with the contoured rack and the pinions the position of the vibrators 56.

The elevator motor 66 is provided with a trip switch 86 and 81 so that when the elevator mechanism is at its highest position, the switch 86 is automatically opened to stop the motor, and when the elevator mechanism is at its lowest position the switch 8! is opened to stop the motor, the starting of the motor being hand-controlled by the operator of the machine.

In order to prevent the sprocket wheels I2 from lifting off the rack I3, due to any upward thrust on the vibratory tubes, tension springs 90 are attached between the plates I and I6, and the cross member I5.

Suspended from the side members II and I2 of the carriage is a cross bar 9| which is disposed above the level of the concretein the roadbed.

To this bar is loosely attached, as by short lengths of chain 92, a curved finishing plate 93 which floats or drags upon the top of the concrete surface directly above the ends of the tubes of the vibrator units 56 in their lowest position.

On the forward end of my machine is provided anoscillating screed arrangement to distribute and level off the unset concrete mix prior to its compaction by the vibrators which are subsequently pulled through it. The screed plate MI is attached to the forward side of a screed frame I03 which extends across the roadway and is provided with shoes I04 which slide on the top edge of the header or side boards 32. The vertical position of the screed plate is adjustable by hand wheels I05 at either end, and contour plates I02 adjustably attached to the screed plate shape the concrete at the edge of the road. Wings I I4 are provided to push any spreading concrete back on to the roadbed. The screed frame is supported from the front cross member I6 of the main frame by bell cranks I06 which are supported by brackets IIII rigidily attached to the member I6. The forward end of each crank is provided with a roller I I0 which supports the screed frame I03 under the channel iron brackets III on the frame, this allowing horizontal movement of the screed frame corresponding to its oscillatory movement across the roadway. The free end of each bell crank is connected by a cable to the control wheel I09 so that the operator may adjust the level of the screed frame as required during operation, to permit the correct amount of concrete to pass thereunder. The forward and backward thrust of the screed IN and the screed frame I03 at any position in its oscillatory movement is taken by the vertical rollers II2 which are mounted on brackets II3 attached tothe front cross member I6, each-rolling between three horizontal rolls H5, 511 and H6 mounted on a bracket I" attached to the screed frame I03.

The oscillatory movement of the screed frame and the screed is provided by an arm H8 attached near the middle of the screed frame and driven by the motor IIO with its speed-reducing unit I20, a crank IZI being provided on its shaft I22.

Referring particularly to the elevating mechanism for the vibrator units,'the relative position of the sprocket wheel I2 on the rack 13 and of the cam roller I9 in the slot I8 determines the angular position and elevation of the gang of vibrator tubes as it is withdrawn from or inserted in the concrete. In Fig. 3 is shown the position of one vibrator unit for 7 different positions on the cam and rack. The ends of the vibrator units are preferably held at the required depth in the concrete until the tubes are substantially vertical, to insure adequate vibration of the concrete adjacent an expansion member.

When it is desired to withdraw the vibrator out of the concrete, for example to avoid striking an expansion member 33 across the roadway, the elevator motor 66 is started and the sprocket wheel I2 advances up the rack I3 and the cam roller I9 follows in the cam slot I8, the relative positions being indicated from A to G. In the final position (G) the vibrator is completely out of the concrete, and as the carriage moves forward the reverse motions take place to insert the vibrator beyond the expansion joint 33, the relative positions being then from G to A. By the use of my mechanism the concrete is thus vibrated to within a short distance of either side of the expansion strip.

While I may use any suitable type of insertible concrete vibrator, I prefer to use one in which a portion of the tubular casing is made semirigid or very stifily flexible. In Fig. 5, the drive shaft 35 of the motor 63 is operatively connected to a vibrator mechanism by means of a relatively short length of flexible shafting 36 connected to the vibrator rotor 39, this shafting being enclosed in a semi-rigid housing 31 of the vibrator mechanism.

The vibrator mechanism consists of an eccentric rotor 39 mounted in bearings 40 which are supported by the rigid housing 38. The short length of flexible shafting 36 is encased in a helical coil 34 which in turn is enclosed within a flexible metallic sheathing 59, and this is enclosed within the semi-rigid housing which may be of rubber-like composition with suitable metallic or fabric reinforcing to give the desired semirigidity. When supported in the concrete, the tube is rigid enough to maintain itself in substantial straight form but is flexible enough so that it may be bent as much as ten to twenty degrees when sufficient force is applied. The advantage of using a semi-rigid tubular vibrator is that it permits the necessary bending either I upwardly or laterally to carry the vibrator units around obstructions, such as manholes and the like, which might be in the roadbed, and thus avoids the necessity of the operator withdrawing the entire gang of vibrators out of the concrete. The semi-rigid tube also gives'a greater efficiency in the vibratory action, because less vibratory energy is dissipated to the motor and from the motor to the supports on the machine.

In operating my machine along a stretch of roadway which has been prepared for concrete pavement, including the insertion of cross expansion joint members, the machine is moved slowly over the area upon which unset concrete has been roughly distributed. The vibrators are lowered into the concrete by' means of the elevator mechanism as described, and are pulled through the leveled-off concrete in an inclined position with the maximum amount of vibration being delivered at a point considerably below the surface of the concrete. As the machine advances, the concrete is distributed and leveled off above the final grade by the screed mechanism at the front of the machine, the extra thickness being gauged depending upon the amount of compaction which the vibrator units produce so that the final grade will be as desired. Any trapped air and excess water has a tendency to follow up the vibrator tubes and the concrete becomes consolidated and no perceptible furrow is left by the vibrators because these are continuously closed behind the moving vibrator tubes. The surface is finished to final grade and texture by the floating curved plate 93 which is located substantially directly above the ends of the vibrator tubes.

While I have illustrated my invention by a preferred embodiment, I do not wish to be restricted to this particular arrangement of parts, but limit the scope of my invention only insofar as required by the prior art and the spirit of the appended claims.

I claim:

1. In a machine for compacting concrete on a roadway, the combination with a carriage frame of vibrator elevator means comprising, a movable support member disposed crosswise of the machine, insertible tubular vibrators supported prong-like on said support member, a rack attached to the carriage frame, a pinion attached to said support member riding on said rack, means to actuate said pinion to cause traverse of the support member along said rack, and cam and follower means between said support and said frame adapted to cooperate with said rack and pinion means to at times move the pronglike ends of the vibrators into and out of the mass of concrete to be vibrated from a substantially vertical position of said vibrators and at times to hold said vibrators in inclined rearwardly partly submerged operative positions.

2. In a machine for compacting concrete, the combination with a carriage frame of vibrator elevator means comprising, a movable support member disposed crosswise of the machine, tubular vibrators attached to said support member, a rack disposed in the direction of travel and attached to the carriage frame adjacent said support member, a cam slot member attached vertically to the carriage frame and disposed in the direction of travel said cam slot and said rack being in general inclined downwardly and forwardly but-not being disposed parallel to each other, a pinion attached to said support member adapted to travel on said rack, a lever arm extending from said support member having a follower adapted to travel in said cam slot, and means to rotate said pinion to cause traverse along said rack, said rack and said slot being disposed relative to each other in vertical position so that the ends of the vibrator tubes fastened to said support may be inserted into or withdrawn from the top of the concrete mass to be vibrated from a substantially vertical position, and at times may be held for operation in the mass in an inclined rearwardly partly submerged operative position.

3. In'a machine for compacting concrete on a roadway, the combination with a carriage frame ofvibrator elevator means comprising: a movable support member disposed crosswise of the machine; a plurality of tubular vibrators attached to said support member adapted to be inserted at least partly in a mass of concrete; racks disposed in the direction of travel inclined downwardly and forwardly attached to the side members of the carriage frame and intermediate thereof; a cam slot member attached vertically to the carriage frame disposed in the direction of travel, the cam slot being inclined downwardly and forwardly; a shaft parallel to said support member and having attached pinions co-acting with said racks; a lever arm extending from said support member having a follower in said cam slot; and means operatively connected to said shaft to rotate the same with its pinions to cause traverse of the support along said racks; said rack and said slot being disposed vertically relative to each other so that as the support member traverses the rack the ends of the vibrator tubes are inserted into or withdrawn from the top of the concrete mass to be vibrated from a substantially vertical position, and at the lower limit of traverse, the tubes are held for operation in the mass in an inclined rearwardly at least partly submerged position.

4. In a machine for compacting concrete on a roadway, vibrator elevator means comprising: contour racks attached to the machines main frame disposed downwardly and forwardly in the direction of travel; a movable support member disposed crosswise of the machine; pinions rotatably attached to said support member and adapted to ride on said racks; a plurality of in-. sertible tubular vibrators attached to said support member; and means operatively connected to said support member adapted to hold it in any selected angular position as it traverses said rack.

5. In a machine for compacting concrete on a roadway, vibrator means comprising: a movable support member disposed crosswise of the machine; pinions rotatably attached to the ends of said support member and intermediate thereof; contour racks attached to the machines frame in the direction of travel upon which said pinions are adapted to ride; means to cause said support to travel along said rack; a plurality of insertible tubular vibrators attached prong-like to said support member; and means operatively connected to said support member adapted to hold it in anyselected angular position as it traverses said rack, whereby the vibrators may be inserted into or withdrawn from the top of the concrete mass to be vibrated from a substantially vertical position and at times may be held for operation in an inclined operative position in the mass.

CHARLES W. PIERCE. 

